DESCRIPTION (Applicant's Abstract): The aim of this project is to further develop and refine the Source of Activation Confusion (SAC) Model by empirically testing unique predictions of SAC and by carefully comparing the data generated by the simulation to the human data. The goal is to achieve a unified account that explains cognitive illusions within the same framework that accounts for normal cognitive functioning, where cognitive illusions provide a window into the workings of the system. Twelve experiments and five modelling projects of the empirical results are proposed. The specific questions chosen to be investigated shed light on important representational and processing assumptions. These questions are: 1) both the Moses Illusion and the rapid feeling of knowing process seem to involve partial or incomplete matching of the probe to a stored memory representation; to what extent can partial matching illusions be explained by activation, per se; 2) is the difference between subliminal and conscious (aware) perception simply a matter of different thresholds on a common activation scale; 3) how and when are hierarchical representations (or higher-level chunks) built and accessed (can we only build one higher level chunk above what is already strong enough to remain active in memory); 4) how are the perceptual features of semantic information represented in memory (are perceptual features of a printed word represented along with the contextual and semantic features of the encoded event); and 5) in addition to accounting for low level cognitive phenomena, can SAC account for higher level phenomena like metacognitive judgments?